Gas fired burners for industrial applications such as deep fryers and ovens typically utilize multiple electrode ignitors to create a spark discharge in a fuel rich area. It is known to fabricate one of the electrodes in the form of a hollow tube and connect that electrode to a fuel line so as to enrich the fuel:air ratio in the immediate vicinity of the spark discharge, thus to enhance the prospects for successful ignition.
A problem associated with fuel gas enriched ignitors of the type described above is the necessity of matching the flow metering characteristics of a hollow electrode to the fuel gas being used; i.e., propane requires a different size metering orifice than natural gas. The known solution is to permanently incorporate a metering orifice into the base of the tubular electrode and assign the device to a single type of fuel. Obviously, this requires the manufacturer or service personnel to inventory at least two different ignitor structures and to label or otherwise segregate the devices so as to avoid inadvertent use of the wrong ignitor in any given situation.
Another problem associated with presently available fuel gas enriched ignitors is the sensing of the enricher flame. The sensor first senses the flame produced by the enricher then sends a signal to the power source to open the main valve for the main burner to ignite. Unless the enricher flame is a large flame, the sensor does not recognize the-flame and the main burner never turns on. To operate properly, a larger metering orifice is used to produce a larger flame. This obviously increases the gas consumption and operating cost and results in waste of unnecessary energy. The existing system also requires an additional solenoid valve dedicated to the electrode which results in higher cost. More important, the sequence of operation takes a longer time due to the extra step in sensing.